1. Field of the Invention
The present invention relates to systems in which transactions are performed by displaying a barcode on a mobile device such as a cellular telephone and using a barcode reader to read the displayed barcode.
2. Description of Related Art
Manufacturers, retailers, event venues, and clubs have long used printed coupons, rebates, tickets, and membership cards with barcode representations to deliver discounts, tickets, and membership information to consumers.
Coupons have typically been delivered by direct mail, or as an insert in a newspaper, or even via in-store displays that contain printed coupons for use by customers. More recently, online coupon centers have been established which allow a customer to electronically find coupons (using a computer) and print them for use in the store (or in conjunction with online purchases).
Even more recently, people have begun delivering electronic coupons containing barcodes to mobile devices for a variety of uses, see for example PCT/GB2003/004131, Forbes, Optimized messages containing barcode information for mobile receiving device, published as WO2004/027662. As employed herein, an electronic coupon may be any collection of information that is identified by a barcode. Electronic coupons offer advantages for both end users and coupon issuers. Because the coupons are electronic, they are much cheaper to issue than paper coupons. Further, the fact that the mobile device can both provide and receive information about the coupon permits kinds of coupons that have no paper coupon equivalents. For example, an electronic coupon may be an n use coupon, that is, a coupon that can be used a predetermined number of times. For the end user, finally, the end user's mobile device doubles as a coupon carrier.
A major problem with electronic coupons is checking the coupon's validity. With paper coupons, validity checking is done by the clerk at the point of sale system. With a standard paper coupon, for example, the clerk at the point of sale checks the coupon to make sure it hasn't expired, passes the coupon's barcode across the barcode reader until the barcode reader confirms that the code has been read, and retains the coupon, thereby ensuring that the coupon is valid when used and used only once. Because the clerk does the validity checking in standard point of sale systems, standard point of sale systems are not set up to deal with invalid coupons. Thus, an important advantage of using mobile devices to display coupons is that the mobile device can do the validity checking. This permits the use of electronic coupons at clerkless point of sale systems and also permits new kinds of coupons such as the n-use coupon described above. Further, because the mobile device has both local and remote information about the coupon and the reading process available to it, it provides a channel for feedback about the coupon generally.
Prior art describes solutions for the validity problem that require the mobile device to contact a central server as part of the process of displaying the coupon's barcode on the mobile device. If the server indicates that the coupon is invalid, the mobile device will not display the barcode. Another method is to provide feedback to a central server in the point of sale system, as disclosed in PCT/GB2003/004131. Disadvantages of these solutions include the following:                They are too slow for use during the standard retail store checkout process.        If the mobile device is not connected to a network at the time the barcode is to be presented, then these solutions are not viable.        If the central server is inoperable at the time the barcode is to be presented, then this solution is not viable.        If the network response time is too slow, then the end user may become frustrated while waiting for the central server to respond and the solution is not viable.        
PCT/US2006/020659 discloses solutions to the foregoing problems. The solutions all involve using the intelligence in the mobile device to respond to validity events. Further work with the techniques disclosed in PCT/US2006/020659 has led to a better understanding of the significance of validity events and to the development of new kinds of coupons that take advantage of the fact that the mobile device can respond to validity events. The new kinds of coupons include:                Coupons which can be shared with another person in a controlled manner.        Supercoupons in which the validity of the super coupon depends upon the performance of a sequence of acts by the recipient of the coupon; and        